Disclosed examples include non-volatile counter systems to generate and store a counter value according to a sensor pulse signal, and power circuits to generate first and second supply voltage signals to power first and second power domain circuits using power from the sensor pulse signal, including a switch connected between first and second power domain supply nodes, a boost circuit, and a control circuit to selectively cause the switch to disconnect the first and second power domain circuits from one another after the first supply voltage signal rises above a threshold voltage in a given pulse of the sensor pulse signal, and to cause the boost circuit to boost the second supply voltage signal after the regulator output is disconnected from the second power domain supply node in the given pulse.